The dibenzodiazepine derivative clozapine is an atypical antipsychotic that has shown efficacy in schizophrenic patients refractory to other antipsychotic drugs. It has been unique in both symptom resolution and improvement in the quality of life (Pickar, 1995). Because of its known risk to cause agranulocytosis (0.80% at 1 yr, 0.91% at 1.5 yr; Alvir et al., 1993), clozapine is restricted to schizophrenic patients for whom other antipsychotic drugs are ineffective and to those who experience intolerable adverse effects.